1. Field of the Invention
The present invention relates generally to mobile communications, and in particular to methods for improving performance of mobile terminals at the cell (or sector) edge region.
2. Discussion of the Related Art
Numerous access schemes exist to allow multiple users to share a communication medium. One such access scheme is known as code division multiple access (CDMA). In CDMA systems, multiple users share the same carrier frequency and may transmit simultaneously.
The current standard for CDMA systems is contained in specifications published by the Telecommunications Industry Association and Electronics Industry Association (TIA/EIA), and include IS-95A, IS-95B, and other CDMA-type protocols. CDMA systems based on IS-95 technologies are generally known as second generation (2G) systems. New standards for enhancing 2G CDMA systems have been developed and offer significant performance improvements compared to the 2G CDMA standard. One such standard is known as cdma2000. cdma2000 is a wideband, spread-spectrum radio interface that uses CDMA technology to satisfy the needs of third generation (3G) wireless communication systems. Several enhancements of the cdma2000 standard have been developed to facilitate the gradual evolution of third generation wireless communication systems. The cdma2000 variant known as 1xEV-DO is being developed to provide high-speed packet data services as an overlay to existing circuit-switched networks.
As the mobile terminal moves around within the network, the channel conditions change continuously due to fast and slow fading, shadowing, number of users, external interference, and other factors. Such problems increase as the mobile terminal moves further away from the serving base stations and into the cell edge region. Techniques for enhancing performance of the mobile terminal at the cell edge region are therefore desirable.